# Derivatives: enter “evaluated at” vertical bar with multiple values as subscripts

Sorry for the long title, but how do I enter evaluated at (for a derivative), with multiple valuation criteria at the bottom of the the big | line?

Thanks!

• Welcome to TeX.SX! You can have a look at our starter guide to familiarize yourself further with our format. – yo' Jul 3 '13 at 20:37
• I think that both answers should be helpful to you. Just for the next time, please add a minimal working example (MWE) that illustrates your problem, starting with \documentclass{...} and ending with \end{document}. It will be much easier for us to reproduce your situation and help you with you problem. – yo' Jul 3 '13 at 20:43

You mean \frac{d}{dx}\Bigr|_{\substack{x=1\\y=2}} from the package \usepackage{amsmath} ?

Is this what you mean? If so, here are three possibilities:

\documentclass{article}
\usepackage{stackengine}
\begin{document}
$$\left. {\frac{\partial x}{\partial t}}% \right|_{% \stackunder[1pt]{\scriptscriptstyle t=0}{\scriptscriptstyle t=1}}$$
~~
$$\left. {\frac{\partial x}{\partial t}}% _{\stackunder[1pt]{}{}}% \right|_{% \stackon[1pt]{\scriptscriptstyle t=0}{\scriptscriptstyle t=1}}$$
~~
$$\left. \frac{\partial x}{\partial t} \right|_{% \stackon[1pt]{\scriptscriptstyle t=0}{\scriptscriptstyle t=1}}$$
\end{document}


• +1 for examples! What are the differences in your three examples in terms of the syntax? I can see the differences in the results, but what do the \stackunder, \stackon and \scriptscriptstyle do in these contexts? Also, what does this do that the \substack macro (from the amsmath package) doesn't do? – jvriesem Mar 24 '15 at 18:56
• @jvriesem I'm not sure how \substack behaves, but having written the stackengine package, I know how it behaves. The \scriptscriptstyle merely sets the math in its smallest standard style associated with subscripts of subscripts. The \stackon will lay the first item on the baseline and place the 2nd item above it, whereas the \stackunder will lay the first item on the baseline and stack the second item below it. In these example, the baseline is where a simple single-line subscript would normally end up. I use a false (empty) stack in example 2 to extend the reach of the |. – Steven B. Segletes Mar 24 '15 at 19:22
• @jvriesem The stackengine package also allows its arguments to be processed, by default, in math mode. Therefore, if you invoke the macro \stackMath in the preamble, you can remove all the \$ delimiters in the stacking arguments. – Steven B. Segletes Mar 24 '15 at 19:33